In mobile radio communication networks, such as cellular telephone systems, neighboring radio cells provide coverage of a geographical area to be serviced. Each cell includes a base station (BS) operating on a set of radio channels. Over such radio channels communications are provided to and from mobile subscribers. A mobile switching center (MSC) controls calls between a group of base stations and the public switched telephone network (PSTN), integrated services digital network (ISDN), and one or more public land mobile radio networks (PLMN). The MSC performs call switching, routing, and charging functions.
All mobile communication networks provide "basic call services" required for making and receiving calls in home and in foreign (hereinafter referred to as "visiting") mobile communication networks. In fact, known cellular systems like the Nordic Mobile Telephone System (NMT), the Total Access Communication System (TACS), the American Digital Cellular System (ADC), the Global System for Mobile Communication (GSM), and the Pacific Digital Cellular System (PDC) have adopted standard techniques for providing such basic services. In addition to connecting calls to/from individual mobile subscribers, basic service may also include services available to all mobile subscribers without requiring an individual service subscription.
Intelligent networks (IN) were developed to provide additional, more flexible services to supplement existing telephony services in the fixed telephony network. More recently, such IN-based services have also become necessary and/or desirable in mobile telecommunications networks. The term "standard supplementary services" is defined to include those supplementary services which generally require an individual subscription before that service can be invoked and which are generally supported by most mobile communication networks. Standard supplementary services include for example call waiting, call forwarding, and call barring. Standard supplementary subscriber services may be divided into two types: (1) those which modify or supplement the process of originating a mobile call and (2) those which modify or supplement the process of terminating a mobile call. Examples of originating supplementary services include: barring of outgoing calls and closed user group. Examples of terminating subscriber services include: barring incoming calls, call forwarding, and call waiting.
A third category of services is network-specific supplementary services. In contrast to the standard supplementary services offered in a standard format by all mobile communication network, network-specific supplementary services are not standardized. Instead, intelligent network type tools and capabilities, particular switch based functions or other means available in the particular network are employed by each operator to quickly design and offer specially tailored services for mobiles being served by that operator's network.
The present invention is particularly concerned with the provision of standard and network-specific supplementary services to mobile subscribers moving between different mobile networks, services areas, location areas, etc. To accommodate the changing location of mobile subscribers, a database is generally required in each mobile communications network to keep track of particular mobile subscribers. In the GSM cellular system, for example, a home location register (HLR) database is implemented as a network node. The HLR stores information for each mobile subscriber such as the mobile subscriber's identification, location, (i.e., the MSC currently serving the present location of the mobile subscriber), and supplementary service information. The HLR typically assists in the managing of supplementary services to the extent that it stores information such as subscriber categories and call forwarding numbers.
The example adopted for purposes of explanation to describe implementation of standard supplementary services and network-specific services is the GSM system coupled with the Customized Applications for Mobile Network Enhanced Logic (CAMEL) standard published by the European Telecommunications Standards Institute (ETSI) as GSM Technical Specification 03.78. The goal of CAMEL is to provide mobile network operators with tools to permit them to readily design and offer new and enhanced mobile services. Such rapid supplementary service development and enhancement are achieved using Intelligent network techniques. A service control point (SCP) is a node that stores and implements service logic underlying supplementary services. A service switching point (SSP) is a node that handles switching functions necessary to enable the services invoked by the SCP.
The set of supplementary services available for a mobile subscriber roaming between different mobile networks depends on support for those services provided by the mobile network currently serving the mobile subscriber. Those services which are not standardized, such as those specifically designed by individual mobile network operators, may well only be supported in that operator's network and nowhere else. In addition, support for supplementary services may also depend on the functionality supported by the serving network elements, e.g., an MSC, protocols and interfaces supported by those network elements, roaming agreements between network operators, and other factors.
Currently, network operator-specific services do not function when the mobile subscriber roams outside of that operator's mobile network. However, this situation is changing. For example, with the introduction of the now evolving GSM, Phase 2+ CAMEL standard, it may be possible to support a number of network operator-specific services to the mobile subscriber when that mobile subscriber is roaming to a visiting network. On the other hand, there will likely always be some services that are only supported in the home mobile communications network.
Consequently, it is and will continue to be difficult for mobile subscribers to know exactly what services are accessible or otherwise provided to them when they enter into different mobile communications networks, service areas, etc. While it is possible to document this information in network operator's manuals, such manuals are unlikely to be carried by the mobile subscriber when he actually needs them. Even if such manuals are consulted by the user, those manuals would soon be outdated. The updated manuals would need to be redistributed to the subscribers every time the set of services in a particular service area changes. Moreover, looking up service information in manuals for particular service areas is inconvenient and time consuming.
It is an object of the present invention to remedy these shortcomings.
It is a further object of the present invention to provide a real-time, user-friendly indication to mobile subscribers which services are available to a subscriber entering into a new service area like a visiting mobile network.
In the present invention, each mobile subscriber is provided with a first set of services in its home network, location area, or service area. For ease of description, the term "location area" is adopted as a general term referring to any geographical area which may support a different set of mobile services. When the mobile subscriber leaves a first location area and enters a second location area, a second set of services specifically supported by the second location area is communicated to the mobile subscriber. The second set of services may include only those services subscribed to by the mobile subscriber which are supported by the second location area, or the second set may include all services supported by the second location area. The first and second sets of services may be different or they may be the same. More specifically, when the mobile subscriber registers with the second location area, the second set of services supported by that second location area is determined.
In a preferred example embodiment, an intelligent network service makes that determination and communicates the second set of services to the mobile subscriber either by a text message or a voice announcement. An intelligent network control node such as a service control point (SCP) is preferably provided and connected to a home location register (HLR) database associated with the mobile's home location area as well as a visiting location register (VLR) database associated with the second location area. The SCP uses subscriber and location data from the HLR or the VLR and other relevant data available to the SCP to determine the second set of services available to the one subscriber.
In one example embodiment, the SCP sends a text message of the second set of services to the mobile subscriber by way of the HLR and MSC/VLR. In an alternative example implementation, the SCP sends a voice announcement including the second set of services by establishing a separate speech connection from voice announcement equipment to the mobile subscriber using an intelligent network service switching function (SSF) and specialized resource function (SRF).